Film tape for forming a cutting edge on dispenser cartons

ABSTRACT

A tape formed of a polymeric material and having a thickness and stiffness suitable as a cutting edge on a dispensing carton for convolutely wound foil, film or paper, the tape includes a coating of adhesive and is applied at a laminating station in the carton manufacturing process and is generally cut with the forming of the carton blanks, and the cut in the tape may be formed with a serrated edge.

BACKGROUND OF THE INVENTION

1. 1. Field of the Invention

2. This invention relates to a novel tape for forming a cutting edge oncartons or boxes for convolutely wound rolls of film, paper or foilproducts, and in one aspect to a new method for applying a cutting edgein-line with the printing or sheeting station of the cartonmanufacturing machine. The cutting edge is formed of a polymericmaterial adhered to the carton for cutting lengths of material from aroll in the carton.

3. 2. Description of the Prior Art

4. The prior art is replete with teachings of using a rectangulardispensing carton for a roll of sheet material, which material isintended to be dispensed and severed in the desired length from thecarton by the consumer. The cartons generally have a cutter on an edgeof the front panel or on the lid to aid in cutting the material. Thecutter is formed with a saw-toothed edge to guide the cut across thewidth of the sheet material.

5. The saw-toothed or serrated cutting edge has been typically formed ofa metal (EP 352634 A dated 19900131, U.S. Pat. No. 5,078,311) or fromthe carton paper or board impregnated with resin (WO 9635574 A2), or byreinforcing a paper carton with plastic or vulcanized fiber materialswith an ultrasonic fusion member (JP 8309890 A dated 19950522). U.S.Pat. No. 4,405,066 discloses a flip top dispenser carton of the typerelated to the present invention wherein the invention relates to theflaps forming the ends of the carton. It also teaches that thelongitudinally extending free edge of the outer panel is straight and isprovided with a plastic reinforcing strip. The patent teaches thecombination of a straight edge 40 and the reinforcing strip 42 providesa rigid cutting surface for tearing heavier rolls of film such as waxpaper and aluminum foil. The reinforcing plastic is applied to adjacentblanks which are contiguous, such that a single cut, defining the freeedges of both blanks simultaneously forms the side edges of both plasticstrips, producing a cutting edge at lower cost than the metal saw-toothblades.

6. The present invention differs from the prior art in that the presentinvention compares a film tape coated with an adhesive for continuousapplication to a carton fiber board or to the blank to form a resultingreinforced cutting edge on the lid flap or front panel of a carton. Thetape is applied to the carton board during the normal box makingprocess. The tape is formed of a polymeric material which is strongenough to serve the numerous cutting operations on the materialdispensed from the ultimate carton but not as sharp or likely to causeinjury to the consumer as the current methods.

SUMMARY OF THE INVENTION

7. The present invention provides a new film tape coated with adhesivefor application to the carton board of a carton for a convolutely woundroll of sheet material in which the tape serves as the cutting edge onthe carton for the material. The tape is formed of a polymeric filmmaterial in a continuous strip which is stiff enough, when applied tothe free edge of a carton to provide the cutting function. The exposededge may be a straight or a serrated edge. Further, the tape of thepresent invention reduces the number of stations used in the cartonforming machine to apply the cutting edge. The application of a metalcutting edge requires the application station and a station for rivetingor stapling the metal to the blank. The method of the present inventionrequires a laminating step or station in-line with the printing orsheeting station to apply the tape before the blanks are cut orseparated. If the tape is applied to blanks placed in mirror-image toeach other, the tape is applied to both blanks simultaneously and thetape is then cut lengthwise to form the cutting edge on each blank andto separate the blanks.

BRIEF DESCRIPTION OF THE DRAWING

8. The present invention will be further described with reference to theaccompanying drawing wherein:

9.FIG. 1 is a perspective view of a roll of the tape material of thepresent invention:

10.FIG. 2 is a schematic view of the application of the tape to a sheetof fiber board moving through the box forming machine;

11.FIG. 3 is a plan schematic view of the tape applied to the fiberboard and then cut into mirrored pairs of box blanks with the tapeapplied and cut on center to separate the box blanks before the foldingstation;

12.FIG. 4 is a perspective view of a dispenser carton showing thecutting tape applied along the top edge of the front panel forming thecutting edge, and

13.FIG. 5 is a detail view showing the tape applied to two carton blanksand cut to form a saw-tooth or serrated edge.

DESCRIPTION OF THE PREFERRED EMBODIMENT

14. The present invention provides a polymeric tape for forming thecutting edge on a rectangular dispensing carton or box for polymericwrapping film, waxed or other paper, or metal wrapping foil.

15. Referring now to the drawing, the tape 6 comprises a polymericbacking 8 coated with an adhesive 9, preferably a hot melt adhesive. Thetape 6 is transversely or convolutely wound to provide a continuoussupply of tape to a carton making machine such that it can be appliedin-line at a laminating station. The laminating station is in-line withthe printing or sheeting station of the carton forming machine.

16.FIG. 2 schematically illustrates the application of the tape 6 to acarton board 20 as it is advanced through the carton manufacturingmachine in the machine direction. The tape 6 passes over a feed or idlerroller 21 to an applying roller 22 and under a pressure or laminatingroller 23. One or both of the rollers 22 and 23 can be heated to apply atape 6 coated with a hot melt adhesive 9. Beyond the laminating stationis the die cutting station 25 which die cuts the carton blanks from thecarton board 20 and cuts the tape 6 to length on the blank and down themiddle to separate two carton blanks, see FIG. 3.

17. The carton 10 normally includes a front panel 11, a bottom panel 12,a rear panel 14, and a lid 15, which is hingedly joined to the rearpanel 14, and a closing flap 16, joined to the free edge of the lid 15,to cover a portion of the front panel 11. Flanges 17 on the ends of thefront, bottom and rear panels form the ends 18 of the carton 10, and asillustrated the lid 15 can be formed with a flange 19, which is tornaway from the ends of the lid 15 upon opening the carton 10. The carton10 is rectangular, having a length considerably greater than its widthto support a roll of sheet material, i.e., clingfilm, paper or foil, notshown. Typically a cutter blade is riveted to the upper edge of thefront panel 11 or to the free edge of the closing flap 16. In thepresent invention the cutter bar 30 is formed by the polymeric tape 6bonded to the upper free edge of the front panel 11. The cutter bar 30has a straight edge projecting just above but generally parallel withthe top edge of the front panel over which the material is drawn andthen torn across the cutter edge. The tape forming the cutter bar canalso be cut so as to form a saw-toothed or serrated free edge to aid incutting the sheet material.

18. As shown in schematic form in FIG. 5, the tape is applied to blanksin contiguous manner, but spaced between the adjacent edges formed tosupport the cutting bar 30. When the tape is applied to the two movingblanks it is registered with the moving blanks and laminated asexplained above. The tape is then cut and in this manner it can be cutto project just above the edge of the front panel 11 or the flap 16 onthe lid. As illustrated the tape is cut to have a saw-toothed edge.Alternatively, the tape 6 can be formed to be applied to individualblanks and formed with a straight or serrated edge.

19. In the present invention, the tape 6 comprises a film backing 8 andan adhesive 9. The film backing is formed of polyester, polypropylene,polyethylene or similar polymeric material having sufficient strength tosupport the cutting function, and preferably polyester. The backing isheat resistant between about 160°F. (71° C.) and about 350° F. (177°C.), preferably at least 250° F. (125° C.). The backing 8 has athickness between 2 mils (0.05 mm) and 7 mils (0.18 mm), preferably 4mils (0.1 mm), with a width of 0.25 inch (0.60 cm) to 1.25 inches (3.2cm), and preferably the cutting edge on the carton is 0.25 inch (0.60cm) in width. If the tape is applied to blanks placed in mirror imagesto each other, a wider tape is preferred, preferably twice as wide asthat used as the cutting edge on each blank.

20. The adhesive 9 exhibits high adhesion characteristics to the filmbacking and the carton board such that it maintains a good bond underthe normal wear and tear exerted on the carton. A preferred adhesiveformulation is: Wt-% Material Available From 20.0 AC 830 Allied Signal,Inc., Morristown, NJ 4.0 Be Square 195 Bareco Products, Rock Hill, SC28.0 Unitac R99 Union Camp Corporation, Jacksonville, FL 12.0 NorsoleneA110 Sartomer Company, Exton, PA 0.50 Lenox 10 Alphachem InternationalCorp., Lake Oswego, Or. 10.0 AT2820 AT Plastics Edmonton, Alberta Canada25.5 Elvaloy HP771 Dupont, Wilmington, DE

21. Alternatively, for a properly treated film, the adhesive 9 can beany available hot melt adhesive that exhibits high adhesioncharacteristics to carton board. When other hot melt adhesives are used,the tape backing is preferably corona treated to improve adhesion of theadhesive to the backing. Other means of improving the adhesion can alsobe used, such as treating the backing with adhesion promoters.

22. Available hot melts for the adhesive 9 can be any typical hot meltadhesive or hot melt pressure-sensitive adhesive such as anethylene-vinyl acetate copolymer (EVA-based) hot melt adhesive; ametallocene based hot melt pressure-sensitive adhesive such as thosecomprising at least one homogeneous linear or substantially linearinterpolymer of ethylene and at least one C₃ to C₂₀ alpha-olefin;EMA-based hot melt and hot melt pressure-sensitive adhesive (ethylenemethylacrylate); EnBA-based hot melt adhesive (ethylene n-butylacrylate); hot melt adhesives based on polyethylene and polypropylenehomopolymers, copolymers and interpolymers, or rubbery block copolymerhot melt adhesives. In general, if EVA-based hot melt adhesives areused, they typically comprise about 15% to about 40% EVA, about 10% toabout 35% wax, about 20% to about 40% resin, and about 0.2% to about0.4% anti-oxidant. These adhesives exhibit high adhesion characteristicsto the carton board, and the backings 8 can be treated to improve itsadhesion to the adhesives.

23. It is surprising that even though the tape is relatively thin, itperforms as a very good cutting edge, especially when the tape projectsjust above the panel.

24. The tape is used in the carton manufacturing process to be appliedto the carton material as the same moves through the carton formingmachine in the machine direction. The tape is applied at one station inthe process to laminate the adhesive coated surface against the cartonboard and is then cut to form a cutting edge along the edge of the frontpanel or the closing flap on the lid. The tape may be cut to form astraight edge or a serrated edge. Alternatively, the tape is cut to formserrations along one edge during the manufacture of the rolls of tape.The application of the cutting edge tape takes place at one station andafter a registered amount of tape is dispensed, registered and laminatedto the carton board adjacent the edge of the carton board forming thefree upper edge of the front panel, it is cut from the roll.

25. For the embodiment where the cutting edge extends beyond the edge ofthe front panel of the carton, whether the edge is straight or serrated,the adhesive is coated on the backing such that the exposed edge is freeof adhesive, if the adhesive used is pressure-sensitive. If the adhesiveus becomes cured after application, then the adhesive can be present onthe exposed edge as well.

26. The adhesive thickness ranges from a coating weight of about 3 toabout 10 g/sq ft (g/929 cm²), preferably of about 3.3 to about 4 g/sqft. (g/929 cm²).

27. An alternative way of using the tape to form a cutting mechanism isto apply the tape to carton board that will be cut into a singlerectangular shape that can act as an insert into the box that holds theroll of film to be cut. A wide tape can be used so that the inserts canbe made in a mirror image and the tape can be cut down the center with ½ending up on each insert. The top edge of the insert can be either astraight edge or a serrated pattern. Alternatively the tape can beapplied along the edge of the carton board so that it extends above theedge of the carton board when the insert is cut out, providing a sharpersurface against which to tear the film to be cut.

28. Inserts produced in the method described above can be inserted ascutting mechanisms into dispensing cartons made of carton board orlarger institutional dispensing boxes made of corrugated.

29. When the tape is used in a fashion such that it extends above theedge of the carton board, the tape can be manufactured so that only ½ofthe surface is coated with adhesive. This would assure that the surfaceof tape that extends above the carton board is free of adhesive on bothsides.

30. Having disclosed the present invention and equivalents thereof, itis to be understood that other changes can be made therein withoutdeparting from the spirit and scope of the invention claimed in theappended claims.

What is claimed is:
 1. An adhesive tape for use as a cutter bar fordispensing cartons, said adhesive tape comprising: a) a backing ofbetween about 2 mils (0.05 mm) to about 7 mils (0.18 mm) in thicknesscomprised of a polymeric film material selected from the groupconsisting of polyester, polypropylene and polyethylene, and b) saidbacking having opposite edges, and opposite sides, one of said sidesbeing coated with an adhesive having high adhesion to a fiber board forforming dispensing cartons.
 2. The tape of claim 1 wherein one edge ofthe tape is formed with a saw-toothed edge.
 3. The dispensing carton ofclaim 1 wherein said cutting edge is a straight edge.
 4. The tape ofclaim 1 wherein said adhesive is selected from the group consisting ofheat activated hot melt adhesives and hot melt pressure sensitiveadhesives.
 5. The tape of claim 4 wherein said adhesive is an EVA basedhot melt adhesive.
 6. The tape of claim 5 wherein said backing is coronatreated.
 7. A method of forming a cutting edge on a dispensing cartonfor film, foil or paper comprising the steps of: a) forming a tapehaving a polymeric backing coated with an adhesive on one side, b)supplying a roll of said tape to the application station in a boxforming machine, c) applying the tape to the carton board in the boxforming machine and laminating the same, and d) cutting the carton boardinto carton blanks and the tape lengthwise to form a cutting edge oneach blank.
 8. The method of claim 7 wherein the method includes thestep of die cutting the carton board and the tape to form a serratededge in the tape adhered to the carton board.
 9. The method of claim 7wherein the method includes the step of cutting the tape backing to forma serrated edge along an edge of the tape.
 10. The method of claim 7wherein the tape comprises a backing formed of a polymeric materialselected from the group consisting of polyester, polyethylene andpolypropylene.
 11. The method according to claim 10 wherein the adhesivecomprises an EVA hot melt adhesive.
 12. The tape of claim 1 wherein saidbacking is heat resistant between about 160° F. (71° C.) and about 350°F. (177° C.).
 13. The method according to claim 11 wherein said backingis corona treated.
 14. A dispensing carton for use in dispensing foil,paper and film comprising: a) a front panel, a bottom panel, a rearpanel, each having panels at opposite ends to form the ends of thecarton; b) a lid connected to the rear panel and a flange joined to thelid to overlap said front panel; and c) a cutting edge formed on one ofsaid front panel and said flange joined to said lid for severing lengthsof material dispensed from said carton, said cutting edge formed of apolymeric material selected from the group comprising polyester,polypropylene and polyethylene and having a thickness between 2 mils(0.05 mm) and 7 mils (0.18 mm) and adhered to said one of said panel andflange by adhesive.
 15. The dispensing carton of claim 14 wherein theadhesive comprises an EVA hot melt adhesive.
 16. The dispensing cartonof claim 14 wherein the polymeric material backing is heat resistantbetween about 160° F. (71° C.) and about 350° F. (177° C.).
 17. Thedispensing carton of claim 14 wherein said cutting edge has a serratededge.
 18. The dispensing carton of claim 14 wherein the cutting edgeprojects above the edge of the front panel.
 19. The dispensing carton ofclaim 14 wherein said backing is corona treated.
 20. The dispensingcarton of claim 14 wherein said cutting edge is a straight edge.